In recent years, wearable motion-assist devices have been developed, separately from autonomous robots. A wearable motion-assist device is wearable by a human body for assisting human activity of the human body. The wearable motion-assist device assists the motion of the wearer. The assistance is implemented by acquiring bioelectrical signals (biological information including, for example, myoelectric potential signals, neurotransmission signals, and brain wave detection signals) of the wearer, and supplying power in accordance with the intention of the wearer, to an actuator of the wearable motion-assist device, based on the acquired bioelectrical signals (see patent documents 1 through 3).
Meanwhile, it is known that doctors and physical therapists conduct rehabilitation for patients who cannot move their bodies due to factors such as cerebral apoplexy and spinal cord injury, for the purpose of recovering muscle strength and preventing muscle strength from declining.
Typically, the doctor or physical therapist directly faces the patient and confirms the state of the patient while conducting the rehabilitation. However, even if the patient cannot come to the hospital because the patient cannot move his/her body, etc., rehabilitation can be conducted by bi-directionally communicating audio-visual signals between the patient and the doctor via a network.    Patent Document 1: Japanese Laid-Open Patent Application No. 2005-95561    Patent Document 2: Japanese Laid-Open Patent Application No. 2005-230099    Patent Document 3: Japanese Laid-Open Patent Application No. 2005-253650
However, in order to recognize the state of the patient, the conventional rehabilitation method is dependent on information conveyed from the patient to the doctor and findings of the doctor. Thus, the doctor cannot objectively know (recognize) the state of the patient. More specifically, the doctor cannot objectively recognize how much the patient is trying to move his/her body, or how much the patient's body is actually moving.
In order to effectively conduct the rehabilitation, the doctor needs to objectively recognize the state of the patient. However, with the conventional rehabilitation method, it has been difficult to effectively conduct the rehabilitation.
Accordingly, there is a need for a motion-assist system of a wearable motion-assist device, a wearable motion-assist device, and a motion-assist method of the wearable motion-assist device, with which the state of a target of motion assistance, such as a patient or a trainee, can be objectively recognized to effectively conduct motion assistance such as rehabilitation and training.